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Dual-channel optical sensing platform for detection of diminazene aceturate based on thioglycolic acid-wrapped cadmium telluride/cadmium sulfide quantum dots

Hao, Chenxia, Zhou, Tao, Liu, Shaopu, Wang, Linlin, Huang, Bowen, Kuang, Nianxi, He, Youqiu
Journal of colloid and interface science 2016 v.472 pp. 76-83
cadmium, diminazene, electrostatic interactions, fluorescence, milk, quantum dots, sulfides
A dual-channel optical sensing platform which combines the advantages of dual-wavelength overlapping resonance Rayleigh scattering (DWO-RRS) and fluorescence has been designed for the detection of diminazene aceturate (DA). It is based on the use of thioglycolic acid-wrapped CdTe/CdS quantum dots (Q-dots). In the absence of DA, the thioglycolic acid-wrapped CdTe/CdS Q-dots exhibit the high fluorescence spectrum and low RRS spectrum, so are selected to develop an easy-to-get system. In the presence of DA, the thioglycolic acid-wrapped CdTe/CdS Q-dots and DA form a complex through electrostatic interaction, which result in the RRS intensity getting enhanced significantly with new RRS peaks appearing at 317 and 397nm; the fluorescence is powerfully quenched. Under optimum conditions, the scattering intensities of the two peaks are proportional to the concentration of DA in the range of 0.0061–3.0μgmL⁻¹. The detection limits for the two single peaks are 4.1ngmL⁻¹ and 3.3ngmL⁻¹, while that of the DWO-RRS method is 1.8ngmL⁻¹, indicating that the DWO-RRS method has high sensitivity. Besides, the fluorescence also exhibits good linear range from 0.0354 to 10.0μgmL⁻¹ with a detection limit of 10.6ngmL⁻¹. In addition, the system has been applied to the detection of DA in milk samples with satisfactory results.